We found this sophisticated meter circuit in an article in Radio Electronics magazine from June 1959. The article taught how to assemble it. Transistors are common types at the time.
This circuit was found in an American documentation from the 90's. The circuit can use almost any...
This circuit triggers a relay when light strikes a sensor. The sensitivity is adjusted in the...
We found this circuit on the internet, but it has some problems. It will be convenient to limit the...